In order to reduce the frequency of replacement of a collection member of a particle detector and in order to reduce the cost for particle detection, a cleaning tool that removes minute foreign substances attracted to the collection member uses a brush member.
Although it is a brush member used not for a particle detector but for an electrophotographic device, examples of the related-art brush member include a brush member described in Japanese Unexamined Patent Application Publication No. 2004-77920 (PTL 1).
The brush member described in PTL 1 is formed by arranging a plurality of chemical-fiber bristles parallel to one another, holding root portions of the bristles by chemical-fiber holding threads extending in a direction intersecting a direction in which the bristles extend, and napping the tips of the bristles. The tips of the bristles of the brush member are brought into contact with a component to be cleaned during use in the electrophotographic device. By applying an ultrasonic wave or a high frequency to the bristles and the holding threads, the bristles and the holding threads are fused and heat welded to one another.
Japanese Unexamined Patent Application Publication No. 10-23927 (PTL 2) describes a brush member for an electrophotographic device as follows: that is, an electrically conductive brush includes a plurality of electrically conductive bristles arranged parallel to one another and a holding portion that holds the bristles on one side of the bristles. The lengths of the bristles of the electrically conductive brush on end portion sides are shorter than those in the other portions.